1. Field of the Invention
The present invention relates to a discharge lamp, a light source apparatus that is equipped with this discharge lamp, and an exposure apparatus that is equipped with this light source apparatus.
2. Description of Related Art
An exposure apparatus, such as a full field exposure type (stationary exposure type) projection exposure apparatus (e.g., a stepper) or a scanning exposure type projection exposure apparatus (e.g., a scanning stepper) that transfers a pattern formed on a reticle (or a photomask and the like) to a wafer (or a glass plate and the like) that is coated with a resist, is used in a lithographic process for fabricating various devices (such as microdevices and electronic devices). An exposure light source apparatus that comprises a combination of a discharge lamp, such as a mercury lamp, and a condenser mirror is conventionally used in such an exposure apparatus, and that discharge lamp is held via a prescribed mounting mechanism.
In one example of a conventional discharge lamp mounting mechanism, a flange part and a ring shaped groove part are provided to a base of the discharge lamp, an open part of a leaf spring is engaged with the groove part, and the flange part is pressed against and fixed to a bracket by that leaf spring (e.g., refer to Japanese Unexamined Patent Application, Publication No. H10-55713). When mounting or replacing a discharge lamp with this mechanism, it is necessary to slide the leaf spring so that a clamp mechanism thereof can be loosened and the open part of the leaf spring can pass through the base. In addition, in another example of a conventional discharge lamp mounting mechanism, a positioning pin or the like is provided to the base of the discharge lamp in advance, the base is fixed by inserting it into a circular open part, which is provided in a flat plate shaped mounting plate, at a prescribed rotational angle and then tightening a slotted part, which is provided in the open part, with a bolt (e.g., refer to Japanese Unexamined Patent Application, Publication No. 2003-45219).
In addition, among conventional light source apparatuses that have a discharge lamp, there is a type that comprises a cooling mechanism for reducing the effects of heat generation. In one example of a conventional cooling mechanism, cooled air is supplied from an outer surface of one base of the discharge toward an outer surface of another base via an outer surface of a bulb part (e.g., refer to Japanese Unexamined Patent Application, Publication No. H09-213129). In another example of a known conventional cooling mechanism, a ring shaped groove part is provided to a base of a discharge lamp, and cooled air is supplied to a bulb part via the groove part and a prescribed ventilation pipe (e.g., refer to Japanese Unexamined Patent Application, Publication No. H11-283898).
With the discharge lamp mounting mechanism in a conventional light source apparatus, when mounting or replacing the discharge lamp, it is necessary either to loosen the clamp mechanism of the leaf spring and slide the leaf spring, or to loosen the clamp of the mounting plate slotted part, and consequently there is a problem in that it takes time, for example, to mount the discharge lamp. In addition, with the conventional mounting mechanism, the base of the discharge lamp is fixed either by engaging one part of the contour of the open part provided to the leaf spring with the groove part of the base, or by tightening the slotted part of the mounting plate, and consequently there is a problem in that it is difficult to set the force by which the base is fixed so that it falls within a target range.
In addition, with the discharge lamp cooling mechanism in the conventional light source apparatus, a cold blast is blown principally against the bulb part of the discharge lamp, and consequently there is a problem in that the cooling action with respect to the base is small.
A first object of the present invention to provide a light source apparatus wherein it is possible, for example, to mount a discharge lamp to a mounting mechanism easily in a short amount of time, as well as to make it possible to easily set.
In addition, it is a second object of the present invention to provide a light source apparatus wherein it is possible to cool the discharge lamp efficiently with a simple mechanism.
It is yet another object of the present invention to provide a discharge lamp that can be adapted to such a light source apparatus, and exposure technology wherein that light source apparatus is used.